How does Jack Butler use imagery in Nightshade?

Examples of Imagery:

"He was a boy who looked about my age: seventeen, maybe eighteen. Brown hair with a slight shimmer of gold fell in a mes around his face. Sweat had caked strands of it to his forehead and cheeks." pg. 8

"I ran up the eastern slope of the mountain. The frosted earth bit into my paws. I knew where I was headed and didn't pause until I arrived at my intended destination. When I reached the ridge, I dropped onto my haunches. He was there, quietly waiting for me, and I wasn't as surprised as I thought I would be." pg. 76